The present invention relates to a storage apparatus used in a computer, an information processing apparatus and the like and more particularly to a magnetic head contacting with a storage medium continuously and a large capacity magnetic storage apparatus using the magnetic head.
A semiconductor memory and a magnetic memory are mainly used as a storage apparatus of an information apparatus. The semiconductor memory is used as an internal storage apparatus from the viewpoint of an access time and the magnetic memory is used as an external memory unit from the viewpoint of a large capacity and non-volatility. The mainstream of the magnetic memory is a magnetic disk and a magnetic tape. These memories use an Al substrate or a tape made of synthetic resins having a magnetic thin layer as a medium thereof. In order to write magnetic information into the medium, a functional unit utilizing electromagnetic conversion operation is used. Further, in order to reproduce the magnetic information stored in the medium, another functional unit utilizing the magnetoresistive phenomenon, the giant magnetoresistive phenomenon or the electromagnetic induction phenomenon is used. These functional units are arranged in an input/output part named a magnetic head.
FIG. 1 is a schematic diagram illustrating a magnetic disk apparatus. A mechanical unit 10 of the magnetic disk apparatus includes a storage medium 1, a motor 2 for driving the storage medium, a magnetic head 3, and an actuator 5 for controlling a position of the magnetic head. The actuator 5 receives a positioning signal from a positioning circuit 41. When a write command signal is applied to a control circuit 40 from an external apparatus, the control circuit calculates a position to which the magnetic head 3 is to be moved and sends a signal to the positioning circuit 41. When the magnetic head is positioned completely, a writing signal (write information) is transmitted from the control circuit 40 to an input/output functional unit provided in the magnetic head. This signal is produced on the basis of a reference clock synchronized with a rotational speed of the storage medium.
When a read command signal is inputted from the external apparatus, the control circuit 40 calculates a position in which magnetic information is present and sends a signal to the positioning circuit 41 so as to move the magnetic head 3 to this position. When the positioning of the magnetic head is completed, the control circuit 40 actuates the input/output functional unit of the magnetic head 3 to detect the magnetic information. The read information is outputted to the external apparatus at a predetermined timing. The control circuit 40 can also produce an ON/OFF signal to be supplied to the motor 2 so as to rotate the storage medium 1 only when the signal is supplied to the control circuit from the external apparatus.
The magnetic head 3 is moved relatively to the storage medium 1 so that magnetic information is written into any position on the medium and the magnetic information is electrically reproduced to be read therefrom if necessary. It is necessary to develop the high density memorization technique in order to write a lot of information into one apparatus.
In order to achieve the high density memorization, a strong magnetic field is required to act on a small area. The magnetic field participates in transmission of information between the input/output functional unit disposed in the magnetic head and the storage medium and when a distance between the magnetic head and the medium is separated, the magnetic field is attenuated rapidly. Accordingly, in order to attain the high density memorization, it is necessary to bring the magnetic head near to the storage medium. In a recent magnetic disk apparatus, the storage medium and a magnetic pole of the input/output functional unit are brought near to each other so that a distance therebetween is within 0.1 .mu.m. Thus, the magnetic head is airborne or flown on the storage medium in order to control the distance stably. The flying height of the magnetic head in the air is required to be held fixed upon input/output of information and accordingly the relative speed of the magnetic head and the medium is maintained fixed in a certain range. It is apparent that there is a possibility that a magnetic storage apparatus having the memory density of 2 Gb/in.sup.2 class can be attained by using the technique for air bearing the magnetic head.
The storage apparatus is required to store information with the higher density in view of miniaturization of recent information apparatuses and increase of information content. In order to attain this requirement, there is proposed a contact recording method in which a magnetic head is brought into contact with a medium to perform input/output operation (R/W). For example, U.S. Pat. No. 5,174,012 discloses a magnetic head structure (including a supporting arm) and U.S. Pat. Nos. 5,163,218 and 5,327,310 disclose a point-contact type magnetic head. Further, EP-A-540,282 and U.S. Pat. No. 5,267,104 also disclose a magnetic storage apparatus of a contact recording system.